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STM32L151xC STM32L152xC
Functional overview
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The SPIs can be served by the DMA controller.
3.17.4 Inter-integrated
sound
(I
2
S)
Two standard I2S interfaces (multiplexed with SPI2 and SPI3) are available. They can
operate in master or slave mode, and can be configured to operate with a 16-/32-bit
resolution as input or output channels. Audio sampling frequencies from 8 kHz up to 192
kHz are supported. When either or both of the I2S interfaces is/are configured in master
mode, the master clock can be output to the external DAC/CODEC at 256 times the
sampling frequency.
The I2Ss can be served by the DMA controller.
3.17.5 Universal
serial bus (USB)
The STM32L151xC and STM32L152xC devices embed a USB device peripheral
compatible with the USB full-speed 12 Mbit/s. The USB interface implements a full-speed
(12 Mbit/s) function interface. It has software-configurable endpoint setting and supports
suspend/resume. The dedicated 48 MHz clock is generated from the internal main PLL (the
clock source must use a HSE crystal oscillator).
3.18
CRC (cyclic redundancy check) calculation unit
The CRC (cyclic redundancy check) calculation unit is used to get a CRC code from a 32-bit
data word and a fixed generator polynomial.
Among other applications, CRC-based techniques are used to verify data transmission or
storage integrity. In the scope of the EN/IEC 60335-1 standard, they offer a means of
verifying the Flash memory integrity. The CRC calculation unit helps compute a signature of
the software during runtime, to be compared with a reference signature generated at link-
time and stored at a given memory location.